Law-enforcement officers have compared the July 9 murder of a wealthy Florida couple known for their charity toward children with a "military operation," a gripping reminder, experts say, that paramilitary tactics can be turned toward civilian destruction.

Saying the incident described "the worst in man," Escambia County Sheriff David Morgan announced Tuesday that police had apprehended the seven main perpetrators – a group of day laborers and auto detailers.

"A couple of individuals with prior military background" were involved, Sheriff Morgan confirmed. "It was a very well-planned and -executed operation." Robbery was the primary motive, and a safe was stolen from the home, officials said. No further information was available about the suspects' military connections at time of writing.

The speed and method of the attack, which involved two teams – some dressed in ninja-like garb – entering the house from two fronts had all the hallmarks of a SWAT-style intrusion usually seen in drug raids or war zones, say some criminologists. According to surveillance videos from outside the house, the charge and retreat lasted no more than four minutes.

The Federal Bureau of Investigation has long worried about military tactics seeping into general culture. Then, earlier this year, the US Department of Homeland Security issued a report about right-wing extremism that cited concern about veterans being recruited by white supremacist organizations in preparation for a national race war. The report was criticized by veterans groups and some conservative politicians as being unpatriotic.

The planning and the large number of perpetrators make this case highly unusual, says Gary Kleck, a criminology professor at Florida State University in Tallahassee. Unlike most robberies, which are crimes of opportunity, these attackers seemed to expect a confrontation, which carries huge physical and legal risks, including the death penalty, if caught.

"For it to be as carefully planned, coordinated, and executed quickly, that's why police are labeling it as military-style," says Professor Kleck. "The way it was carried out itself seems to justify the label."

Military strategy has become "normalized" in American culture through video games, movies, and the common use of police SWAT teams for even low-level drug raids, says Peter Kraska, an Eastern Kentucky University criminologist who studies SWAT tactics.

"For criminals to take the same kind of approach shouldn't surprise anyone," Professor Kraska says. "You would not only see certain police types attracted to it, but ordinary folks – if they're seduced by it in popular video, they might be seduced by it in real life, as well."

The slain couple, Byrd and Melanie Billings, were high-profile residents of their small Panhandle town whose adoption of 13 children, most with special needs, had been reported in local newspapers. They have 17 children overall, some grown, and nine children were in the house at the time of the attack.

Radley Balko, an editor at Reason magazine, says he's documented growing numbers of cases in which robbers dress up as SWAT teams to get into homes, including a recent case in Maryland's Prince George's County.

Speaking independently from the Florida case, he says, "It's troubling, as SWAT raids become more common, that criminals are sort of learning what's happening with police tactics."